/*
 ** filename : KillLPFSupport.c
 ** compile :
 ** #gcc -Wall -o KillLPFSupport KillLPFSupport.c
 ** usage example :
 ** #./KillLPFSupport
 ** test on :
 ** Ubuntu 12.04LTS / Kernel 3.2.0
 ** source code come from busybox project.
 **/

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <ctype.h>
#include <string.h>
#include <unistd.h>
#include <dirent.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

#define READ_BUF_SIZE 50

/* find_pid_by_name()
 **
 **  This finds the pid of the specified process.
 **  Currently, it's implemented by rummaging through
 **  the proc filesystem.
 **
 **  Returns a list of all matching PIDs
 **/
extern long* find_pid_by_name( char* pidName)
{
    DIR *dir;
    struct dirent *next;
    long* pidList=NULL;
    int i=0;

    dir = opendir("/proc");
    if (!dir)
    {
//                perror_msg_and_die("Cannot open /proc");
        fprintf(stderr, "Cannot open /proc\n");
        exit(1);
    }

    while ((next = readdir(dir)) != NULL)
    {
        FILE *status;
        char filename[READ_BUF_SIZE];
        char buffer[READ_BUF_SIZE];
        char name[READ_BUF_SIZE];

        /* Must skip ".." since that is outside /proc */
        if (strcmp(next->d_name, "..") == 0)
            continue;

        /* If it isn't a number, we don't want it */
        if (!isdigit(*next->d_name))
            continue;

        sprintf(filename, "/proc/%s/status", next->d_name);
        if (! (status = fopen(filename, "r")))
        {
            continue;
        }

        /* Read first line in /proc/?pid?/status */
        if (fgets(buffer, READ_BUF_SIZE-1, status) == NULL)
        {
            fclose(status);
            continue;
        }
        fclose(status);

        /* Buffer should contain a string like "Name:   binary_name" */
        sscanf(buffer, "%*s %s", name);
        if (strcmp(name, pidName) == 0)
        {
            pidList=realloc( pidList, sizeof(long) * (i+2));
            pidList[i++]=strtol(next->d_name, NULL, 0);
        }
    }

    if (pidList)
    {
        pidList[i]=0;
    }
    else
    {
        pidList=realloc( pidList, sizeof(long));
        pidList[0]=-1;
    }
    return pidList;
}


int main(int argc, char *argv[])
{
    int opt, n = 0;
    int single_flag = 0;
    int fail = 1;

    /* do normal option parsing */
    while ((opt = getopt(argc, argv, "s")) > 0 )
    {
        switch (opt)
        {
        case 's':
            single_flag = 1;
            break;
        default:
            printf("usage:\n");
            printf("\t%s processname: list all pids by processname\n", argv[0]);
            printf("\t%s -s processname: list the first pid by processname\n", argv[0]);
        }
    }

    /* Looks like everything is set to go. */
    //optind < argc)

        long *pidList;
        long *pl;
        FILE* cmdfd;
        char buffer[BUFSIZ + 1];
        char buf[256] = {0};
        memset(buffer, '\0', strlen(buffer));

//        pidList = find_pid_by_name(argv[optind]);
        pidList = find_pid_by_name("LPFSupport");
        for(pl = pidList; *pl > 0; pl++)
        {
            strcpy(buffer, "kill -9 ");
            sprintf(buf,"%ld", *pl);
            strcat(buffer, buf);

            cmdfd = popen(buffer, "w");
            if (cmdfd == NULL)
                printf("Popen Error\n");
            pclose(cmdfd);

            printf("%s%ld", (n++ ? " " : ""), *pl);
            fail = 0;
            if (single_flag)
                break;
        }
        free(pidList);
        optind++;

    printf("\n");
    return(fail);
}
